U.S. patent application number 14/728607 was filed with the patent office on 2015-12-10 for cell and preparation method thereof.
The applicant listed for this patent is Ningde Amperex Technology Limited. Invention is credited to Xiang HONG, Jiewei Zhang, Kaifu Zhong.
Application Number | 20150357672 14/728607 |
Document ID | / |
Family ID | 54770316 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150357672 |
Kind Code |
A1 |
HONG; Xiang ; et
al. |
December 10, 2015 |
CELL AND PREPARATION METHOD THEREOF
Abstract
The present disclosure provides a cell and a preparation method
thereof. The cell comprises a positive electrode plate (1); a
negative electrode plate (2) and a composite solid electrolyte
membrane (3) positioned between the positive electrode plate (1)
and the negative electrode plate (2). The composite solid
electrolyte membrane (3) comprises inorganic solid electrolyte
layers (31) and structure supporting layers (32) which are
alternately laminated along a laminating direction (D), and has
abutted surfaces (S1) respectively abutting against the positive
electrode plate (1) and the negative electrode plate (2), an angle
between the laminating direction (D) and the abutted surface (S1)
is defined as .alpha., and
0.degree..ltoreq..alpha..ltoreq.90.degree.. The composite solid
electrolyte membrane not only plays an advantage of a high lithium
ionic conductivity of the inorganic solid electrolyte, but also has
an excellent mechanical processing property, thereby significantly
improving electrochemical performance and safety performance of the
cell.
Inventors: |
HONG; Xiang; (Ningde,
CN) ; Zhang; Jiewei; (Ningde, CN) ; Zhong;
Kaifu; (Ningde, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ningde Amperex Technology Limited |
Ningde |
|
CN |
|
|
Family ID: |
54770316 |
Appl. No.: |
14/728607 |
Filed: |
June 2, 2015 |
Current U.S.
Class: |
429/306 ;
29/623.3; 429/304 |
Current CPC
Class: |
H01M 2300/0082 20130101;
Y02E 60/10 20130101; Y10T 29/49114 20150115; H01M 10/058 20130101;
H01M 10/056 20130101; H01M 10/052 20130101; H01M 10/0562 20130101;
H01M 10/0565 20130101; H01M 2300/0068 20130101 |
International
Class: |
H01M 10/056 20060101
H01M010/056; H01M 10/0525 20060101 H01M010/0525; H01M 10/058
20060101 H01M010/058; H01M 10/0562 20060101 H01M010/0562 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2014 |
CN |
201410251916.4 |
Claims
1. A cell, comprising: a positive electrode plate (1); and a
negative electrode plate (2); the cell further comprising: a
composite solid electrolyte membrane (3) positioned between the
positive electrode plate (1) and the negative electrode plate (2),
comprising inorganic solid electrolyte layers (31) and structure
supporting layers (32) which are alternately laminated along a
laminating direction (D), and having abutted surfaces (S1)
respectively abutting against the positive electrode plate (1) and
the negative electrode plate (2), an angle between the laminating
direction (D) and the abutted surface (S1) being defined as
.alpha., and 0.degree..ltoreq..alpha.<90.degree..
2. The cell according to claim 1, wherein a height a.sub.1 of each
layer of the inorganic solid electrolyte layers (31) along the
laminating direction (D) is 0.1 .mu.m.about.100 .mu.m; a height
a.sub.2 of each layer of the structure supporting layers (32) along
the laminating direction (D) is 0.01 .mu.m.about.100 .mu.m; and
1.ltoreq.a.sub.1/a.sub.2.ltoreq.100.
3. The cell according to claim 2, wherein
10.ltoreq.a.sub.1/a.sub.2.ltoreq.100.
4. The cell according to claim 1, wherein the structure supporting
layer (32) is a polymer layer or a polymer electrolyte layer, a
polymer electrolyte in the polymer electrolyte layer comprises a
polymer and a lithium salt.
5. The cell according to claim 1, wherein the first layer and the
last layer of the composite solid electrolyte membrane (3) each are
the structure supporting layer (32), a height a.sub.2 of the
structure supporting layer (32) at the first layer and a height
a.sub.2 of the structure supporting layer (32) at the last layer
along the laminating direction (D) each are bigger than a height
a.sub.2 of each of the other layers of the structure supporting
layer (32) along the laminating direction (D), the height a.sub.2
of the structure supporting layer (32) at the first layer and the
height a.sub.2 of the structure supporting layer (32) at the last
layer along the laminating direction (D) each are 0.1
.mu.m.about.100 .mu.m.
6. The cell according to claim 1, wherein a thickness (b.sub.1) of
the composite solid electrolyte membrane (3) is 1 .mu.m.about.100
.mu.m.
7. The cell according to claim 6, wherein the thickness (b.sub.1)
of the composite solid electrolyte membrane (3) is 5 .mu.m.about.30
.mu.m.
8. The cell according to claim 1, further comprising: at lest a
buffer layer (4), the buffer layer (4) being positioned between the
composite solid electrolyte membrane (3) and the positive electrode
plate (1), or the buffer layer (4) being positioned between the
composite solid electrolyte membrane (3) and the negative electrode
plate (2), or the buffer layers (4) being positioned between the
composite solid electrolyte membrane (3) and the positive electrode
plate (1) and between the composite solid electrolyte membrane (3)
and the negative electrode plate (2).
9. The cell according to claim 8, wherein a material of the buffer
layer (4) is selected from a lithium-containing inorganic salt, a
thickness (b.sub.2) of each layer of the buffer layer (4) is 1
nm.about.1 .mu.m.
10. A preparation method of a cell, comprising steps of: providing
a positive electrode plate (1); providing a negative electrode
plate (2); preparing a composite solid electrolyte membrane (3):
alternately depositing inorganic solid electrolyte layers (31) and
structure supporting layers (32) on a substrate along a laminating
direction (D) to obtain a composite solid electrolyte material
which has an alternately laminated structure, then separating the
composite solid electrolyte material and the substrate to obtain a
composite solid electrolyte membrane (3), in which the composite
solid electrolyte membrane (3) comprises the inorganic solid
electrolyte layers (31) and the structure supporting layers (32)
which are alternately laminated along the laminating direction (D);
preparing a cell: positioning the obtained composite solid
electrolyte membrane (3) between the positive electrode plate (1)
and the negative electrode plate (2) to form a cell by winding
and/or laminating, in which the composite solid electrolyte
membrane (3) has abutted surfaces (S1) respectively abutting
against the positive electrode plate (1) and the negative electrode
plate (2), an angle between the laminating direction (D) and the
abutted surface (S1) being defined as .alpha., and
0.degree..ltoreq..alpha.<90.degree..
11. The preparation method of the cell according to claim 10,
wherein a height a.sub.1 of each layer of the inorganic solid
electrolyte layers (31) along the laminating direction (D) is 0.1
.mu.m.about.100 .mu.m; a height a.sub.2 of each layer of the
structure supporting layers (32) along the laminating direction (D)
is 0.01 .mu.m.about.100 .mu.m; and
1.ltoreq.a.sub.1/a.sub.2.ltoreq.100.
12. The preparation method of the cell according to claim 11,
wherein 10.ltoreq.a.sub.1/a.sub.2.ltoreq.100.
13. The preparation method of the cell according to claim 10,
wherein the structure supporting layer (32) is a polymer layer or a
polymer electrolyte layer, a polymer electrolyte in the polymer
electrolyte layer comprises a polymer and a lithium salt.
14. The preparation method of the cell according to claim 10,
wherein the first layer and the last layer of the composite solid
electrolyte membrane (3) each are the structure supporting layer
(32), a height a.sub.2 of the structure supporting layer (32) at
the first layer and a height a.sub.2 of the structure supporting
layer (32) at the last layer along the laminating direction (D)
each are bigger than a height a.sub.2 of each of the other layers
of the structure supporting layer (32) along the laminating
direction (D), the height a.sub.2 of the structure supporting layer
(32) at the first layer and the height a.sub.2 of the structure
supporting layer (32) at the last layer along the laminating
direction (D) each are 0.1 .mu.m.about.100 .mu.m.
15. The preparation method of the cell according to claim 10,
wherein a thickness (b.sub.1) of the composite solid electrolyte
membrane (3) is 1 .mu.m.about.100 .mu.m.
16. The preparation method of the cell according to claim 15,
wherein the thickness (b.sub.1) of the composite solid electrolyte
membrane (3) is 5 .mu.m.about.30 .mu.m.
17. The preparation method of the cell according to claim 10,
wherein in the step of preparing the composite solid electrolyte
membrane (3), before or after the composite solid electrolyte
material is separated from the substrate, the composite solid
electrolyte material is cut at an angle of a relative to the
laminating direction (D) to form the abutted surfaces (S1).
18. The preparation method of the cell according to claim 10,
further comprising a step before the step of preparing the cell:
providing a buffer layer (4): a buffer layer (4) is deposited on at
least one surface selected from a group consisting of a surface of
the positive electrode plate (1) facing the composite solid
electrolyte membrane (3), a surface of the negative electrode plate
(2) facing the composite solid electrolyte membrane (3), a surface
of the composite solid electrolyte membrane (3) facing the positive
electrode plate (1) and a surface of the composite solid
electrolyte membrane (3) facing the negative electrode plate (2),
to make the buffer layer (4) positioned between the composite solid
electrolyte membrane (3) and the positive electrode plate (1), or
to make the buffer layer (4) positioned between the composite solid
electrolyte membrane (3) and the negative electrode plate (2), or
to make the buffer layers (4) positioned between the composite
solid electrolyte membrane (3) and the positive electrode plate (1)
and between the composite solid electrolyte membrane (3) and the
negative electrode plate (2).
19. The preparation method of the cell according to claim 18,
wherein a material of the buffer layer (4) is selected from a
lithium-containing inorganic salt, a thickness (b.sub.2) of each
layer of the buffer layer (4) is 1 nm.about.1 .mu.m.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to Chinese patent
application No. CN201410251916.4, filed on Jun. 9, 2014, which is
incorporated herein by reference in its entirety.
FIELD OF THE PRESENT DISCLOSURE
[0002] The present disclosure relates to a field of an
electrochemical device technology, and more specifically relates to
a cell and a preparation method thereof.
BACKGROUND OF THE PRESENT DISCLOSURE
[0003] Since the lithium-ion battery has a higher energy density,
it has been widely applied in consumer electronics, electric
vehicles and energy storage power stations. Conventional
lithium-ion battery uses a liquid electrolyte, a higher lithium
ionic conductivity of the liquid electrolyte facilitates lithium
ions to transmit between a positive electrode plate and a negative
electrode plate. However, a non-aqueous organic solvent in the
liquid electrolyte is easily volatilized and flamed, which has been
a key factor that affects the safety performance of the lithium-ion
battery.
[0004] In order to resolve the safety problems of the lithium-ion
battery, a series of solid electrolytes are developed. These solid
electrolytes comprise polymer solid electrolytes and inorganic
solid electrolytes. The polymer solid electrolyte has excellent
mechanical processability, however, compared with the liquid
electrolyte, the lower electrical conductivity of the polymer solid
electrolyte at room temperature (<10.sup.-4 S/cm) makes them
greatly restricted in applications of the lithium-ion battery. The
recent research discoveries a new sulphur-containing inorganic
solid electrolyte, the electrical conductivity of which may even be
bigger than the electrical conductivity of the conventional liquid
electrolyte, however, because the sulphur-containing inorganic
solid electrolyte has a weaker machanical processing property, it
is difficult to be fabricated into a solid electrolyte membrane
which can be applied in the lithium-ion battery, and the fragility
of the sulphur-containing inorganic solid electrolyte also
restricts its applications in the consumer electronics.
[0005] United States patent document published as No.
US20110081580A1 on Apr. 7, 2011 discloses a method of sintering
inorganic solid electrolyte particles under a higher temperature to
obtain an inorganic solid electrolyte membrane. However, it is very
difficult to obtain an inorganic solid electrolyte membrane with a
very small thickness (<0.1 mm) by using this method, therefore
it is difficult to be applied in higher energy density lithium-ion
battery. Moreover, although the inorganic solid electrolyte
membrane prepared with this method has an excellent ability of
transmitting lithium ions, due to the fragility of the inorganic
solid electrolyte itself, the obtained inorganic solid electrolyte
membrane will have a weaker mechanical strength, which is easily
fractured to lose the ability of transmitting lithium ions when
deformation on the inorganic solid electrolyte membrane occurs.
[0006] United States patent document with an issuance publication
No. U.S. Pat. No. 5,238,759 issued on Aug. 24, 1993 discloses a
method of adding Teflon as an adhesive into an inorganic solid
electrolyte, then rolling or extruding the inorganic solid
electrolyte to obtain an inorganic solid electrolyte membrane. The
inorganic solid electrolyte membrane prepared with this method has
an excellent mechanical processing property, however, since Teflon
has an isolability for lithium ions and the inorganic solid
electrolyte particles in the inorganic solid electrolyte membrane
prepared with this method cannot contact well with each other, the
lithium ionic conductivity of the obtained inorganic solid
electrolyte membrane is relatively small, and the rate performance
of the assembled lithium-ion battery is also worse.
SUMMARY OF THE PRESENT DISCLOSURE
[0007] In view of the problems existing in the background
technology, an object of the present disclosure is to provide a
cell and a preparation method thereof, the composite solid
electrolyte membrane of the cell not only plays an advantage of a
high lithium ionic conductivity of the inorganic solid electrolyte,
but also has an excellent mechanical processing property, thereby
significantly improving the electrochemical performance and the
safety performance of the cell.
[0008] In order to achieve the above object, in a first aspect of
the present disclosure, the present disclosure provides a cell,
which comprises: a positive electrode plate; a negative electrode
plate; and a composite solid electrolyte membrane positioned
between the positive electrode plate and the negative electrode
plate. The composite solid electrolyte membrane comprises inorganic
solid electrolyte layers and structure supporting layers which are
alternately laminated along a laminating direction, and has abutted
surfaces respectively abutting against the positive electrode plate
and the negative electrode plate, an angle between the laminating
direction and the abutted surface is defined as .alpha., and
0.degree..ltoreq..alpha.<90.degree..
[0009] In a second aspect of the present disclosure, the present
disclosure provides a preparation method of a cell, for preparing
the cell of the first aspect, comprises steps of: providing a
positive electrode plate; providing a negative electrode plate;
preparing a composite solid electrolyte membrane: alternately
depositing inorganic solid electrolyte layers and structure
supporting layers on a substrate along a laminating direction to
obtain a composite solid electrolyte material which has an
alternately laminated structure, then separating the composite
solid electrolyte material and the substrate to obtain a composite
solid electrolyte membrane, in which the composite solid
electrolyte membrane comprises the inorganic solid electrolyte
layers and the structure supporting layers which are alternately
laminated along the laminating direction; preparing a cell:
positioning the obtained composite solid electrolyte membrane
between the positive electrode plate and the negative electrode
plate to form a cell by winding and/or laminating, in which the
composite solid electrolyte membrane has abutted surfaces
respectively abutting against the positive electrode plate and the
negative electrode plate, an angle between the laminating direction
and the abutted surface is defined as .alpha., and
0.degree..ltoreq..alpha.<90.degree..
[0010] The present disclosure has following beneficial effects:
[0011] 1. The composite solid electrolyte membrane of the cell of
the present disclosure comprises alternately laminated inorganic
solid electrolyte layers and structure supporting layers, the
inorganic solid electrolyte particles in the inorganic solid
electrolyte layer keep a well contact with each other, thereby well
ensuring the structural integrity of the transmission channel of
the lithium ions, therefore the composite solid electrolyte
membrane can play an advantage of a high lithium ionic conductivity
of the inorganic solid electrolyte.
[0012] 2. In the composite solid electrolyte membrane of the cell
of the present disclosure, due to the existance of the structure
supporting layer, the composite solid electrolyte membrane has an
excellent mechanical processing property, thereby significantly
improving the electrochemical performance and the safety
performance of the cell.
[0013] 3. A very thin and excellent composite solid electrolyte
membrane can be obtained from the preparation method of the cell of
the present disclosure, and the fragility of the inorganic solid
electrolyte layer can be overcome in the assembling process and the
using process of the cell, therefore the composite solid
electrolyte membrane can be well applied in the cell.
[0014] 4. The laminated structure of the inorganic solid
electrolyte layer and the structure supporting layer of the
composite solid electrolyte membrane of the present disclosure
layer is simple, the cutting operation is easy, therefore the mass
production can be easily performed, and it will have great
significance on developing a full-solid-state cell with high
performance.
BRIEF DESCRIPTION OF THE FIGURES
[0015] FIG. 1 is an exploded view illustrating a cell of an
embodiment of the present disclosure;
[0016] FIG. 2 is an assembled view illustrating the cell of FIG.
1;
[0017] FIG. 3 is a schematic view illustrating a forming process of
a composite solid electrolyte membrane of the cell in FIG. 1 and
FIG. 2;
[0018] FIG. 4 is an exploded view illustrating a cell of another
embodiment of the present disclosure;
[0019] FIG. 5 is an assembled view illustrating the cell of FIG.
4;
[0020] FIG. 6 is an exploded view illustrating a cell of another
embodiment of the present disclosure;
[0021] FIG. 7 is an assembled view illustrating the cell of FIG.
6;
[0022] FIG. 8 is a schematic view illustrating a forming process of
a composite solid electrolyte membrane of the cell in FIG. 6 and
FIG. 7;
[0023] FIG. 9 is a schematic view illustrating the composite solid
electrolyte membrane of FIG. 8 before an upper corner and a lower
corner are cut away;
[0024] FIG. 10 is a schematic view illustrating the composite solid
electrolyte membrane in FIG. 9 after the upper corner and the lower
corner are cut away;
[0025] FIG. 11 is a schematic view illustrating the composite solid
electrolyte membrane of FIG. 10 after being rotated, the rotated
composite solid electrolyte membrane presents a same orientation of
FIG. 7;
[0026] FIG. 12 is a sectional view illustrating a cell formed from
the composite solid electrolyte membrane of FIG. 9 before the upper
corner and the lower corner are cut away;
[0027] FIG. 13 is an assembled view illustrating the cell of FIG.
12;
[0028] FIG. 14 is a schematic view illustrating the cell of FIG. 13
after being rotated.
[0029] Reference numerals of the embodiments are represented as
follows: [0030] 1 positive electrode plate [0031] 2 negative
electrode plate [0032] 3 composite solid electrolyte membrane
[0033] 31 inorganic solid electrolyte layer [0034] 32 structure
supporting layer [0035] 4 buffer layer [0036] D laminating
direction [0037] S1 abutted surface [0038] S2 laminated surface
[0039] a.sub.1 height [0040] a.sub.2 height [0041] b.sub.1
thickness [0042] b.sub.2 thickness [0043] T thickness direction
[0044] H height direction [0045] L length direction
DETAILED DESCRIPTION
[0046] Hereinafter a cell and a preparation method thereof and
examples, comparative examples and test results according to the
present disclosure will be described in detail.
[0047] Firstly, a cell according to a first aspect of the present
disclosure will be described,
[0048] Referring to FIGS. 1-2, FIGS. 4-7 and FIGS. 12-14, a cell
according to a first aspect of the present disclosure comprises: a
positive electrode plate 1; a negative electrode plate 2; and a
composite solid electrolyte membrane 3 positioned between the
positive electrode plate 1 and the negative electrode plate 2. The
composite solid electrolyte membrane 3 comprises inorganic solid
electrolyte layers 31 and structure supporting layers 32 which are
alternately laminated along a laminating direction D, and has
abutted surfaces S1 respectively abutting against the positive
electrode plate 1 and the negative electrode plate 2, an angle
between the laminating direction D and the abutted surface S1 is
defined as .alpha., and 0.degree..ltoreq..alpha.<90.degree.. In
FIGS. 1-2 and FIGS. 4-5, since the laminating direction D is
parallel to the abutted surface S1, the angle .alpha. is not
illustrated.
[0049] In the cell according to the first aspect of the present
disclosure, the composite solid electrolyte membrane 3 may have an
ability of transmitting lithium ions or sodium ions.
[0050] In the cell according to the first aspect of the present
disclosure, referring to FIG. 1, FIG. 4, FIG. 6 and FIG. 12, the
laminated surfaces S2 between the alternately laminated inorganic
solid electrolyte layers 31 and the structure supporting layers 32
may be parallel to each other.
[0051] In the cell according to the first aspect of the present
disclosure, referring to FIGS. 1-2, and FIGS. 4-5, a may be
0.degree..
[0052] In the cell according to the first aspect of the present
disclosure, the inorganic solid electrolyte in the inorganic solid
electrolyte layer 31 may be at least one selected from a group
consisting of lithium-containing oxide with perovskite structure,
lithium-containing metal phosphate with Nasicon structure,
lithium-containing metal oxide with garnet structure, glassy or
ceramic lithium-ion conductor and lithium-containing sulfide with
Thio-Lisicon structure.
[0053] In the cell according to the first aspect of the present
disclosure, the lithium-containing oxide with perovskite structure
may be selected from La.sub.0.55Li.sub.0.35TiO.sub.3; the
lithium-containing metal phosphate with Nasicon structure may be
selected from LiTi.sub.2(PO.sub.4).sub.3--AlPO.sub.4; the
lithium-containing metal oxide with garnet structure may be
selected from Li.sub.6BaLa.sub.2Ta.sub.2O.sub.12; the glassy or
ceramic lithium-ion conductor may be selected from Li.sub.3N; the
lithium-containing sulfide with Thio-Lisicon structure may be
selected from Li.sub.2S(75%)-P.sub.2S.sub.5(25%) or
Li.sub.3.25Ge.sub.0.25P.sub.0.75S.sub.4.
[0054] In the cell according to the first aspect of the present
disclosure, referring to FIG. 1, FIG. 4, FIG. 6 and FIG. 12, a
height a.sub.1 of each layer of the inorganic solid electrolyte
layers 31 along the laminating direction D may be 0.1
.mu.m.about.100 .mu.m.
[0055] In the cell according to the first aspect of the present
disclosure, the structure supporting layer 32 may be a polymer
layer.
[0056] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
layer, a polymer in the polymer layer may be at least one selected
from a group consisting of vinylidene fluoride-hexafluoropropylene
copolymer (PVDF-HFP), polyacrylonitrile (PAN), polymethyl
methacrylate (PMMA), polyethylene oxide (PEO), polyimide (PI),
polyethylene (PE), polypropylene (PP), polytetrafluoroethene (PTFE)
and ethylene-propylene-diene terpolymer (EDPM).
[0057] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
layer, a weight-average molecular weight of the polymer in the
structure supporting layer 32 may be 50,000.about.10,000,000.
[0058] In the cell according to the first aspect of the present
disclosure, the structure supporting layer 32 may also be a polymer
electrolyte layer.
[0059] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
electrolyte layer, a polymer electrolyte in the polymer electrolyte
layer may comprise a polymer and a lithium salt.
[0060] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
electrolyte layer, the polymer of the polymer electrolyte may be
one selected from a group consisting of polyether, polythioether
and polyamine.
[0061] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
electrolyte layer, the polyether may be selected from polyethylene
oxide (PEO) or polypropylene oxide (PPO); the polythioether may be
selected from polyethyl sulfide (PES) or polyphenylene sulfide
(PPS); the polyamine may be selected from polyethylene diamine
(PEA).
[0062] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
electrolyte layer, the lithium salt of the polymer electrolyte may
be at least one selected from a group consisting of lithium
hexafluorophosphate (LiPF.sub.6), lithium tetrafluoroborate
(LiBF.sub.4), lithium chloride (LiCl), lithium aluminum
tetrachloride (LiAlCl.sub.4), lithium trifluoromethane sulfonate
(LiCF.sub.3SO.sub.3), 2,2,2-trifluoro lithium acetate
(LiCF.sub.3CO.sub.2), lithium bis(trifluoromethane)sulfonimide
(LiN(CF.sub.3SO.sub.2).sub.2), lithium hexafluoroarsenate
(LiAsF.sub.6), lithium bis(fluorosulfony)imide (LiFSI), lithium
bis(trifluoromethanesulphonyl)imide (LiTFSI) and lithium
bis(oxalate)borate (LiBOB).
[0063] In the cell according to the first aspect of the present
disclosure, when the structure supporting layer 32 is the polymer
electrolyte layer, the weight-average molecular weight of the
polymer in the structure supporting layer 32 may be
50,000.about.10,000,000.
[0064] In the cell according to the first aspect of the present
disclosure, referring to FIG. 1, FIG. 4, FIG. 6 and FIG. 12, a
height a.sub.2 of each layer of the structure supporting layers 32
along the laminating direction D may be 0.01 .mu.m.about.100
.mu.m.
[0065] In the cell according to the first aspect of the present
disclosure, a ratio between the height a.sub.1 of each layer of the
inorganic solid electrolyte layers 31 along the laminating
direction D and the height a.sub.2 of each layer of the structure
supporting layers 32 along the laminating direction D, that is
a.sub.1/a.sub.2, may meet 1.ltoreq.a.sub.1/a.sub.2.ltoreq.100,
preferably may meet 10.ltoreq.a.sub.1/a.sub.2.ltoreq.100.
[0066] In the cell according to the first aspect of the present
disclosure, referring to FIG. 1, FIG. 4, FIG. 6 and FIG. 12, the
first layer and the last layer of the composite solid electrolyte
membrane 3 each may be the structure supporting layer 32, a height
a.sub.2 of the structure supporting layer 32 at the first layer and
a height a.sub.2 of the structure supporting layer 32 at the last
layer along the laminating direction D each may be bigger than a
height a.sub.2 of each of the other layers of the structure
supporting layer 32 along the laminating direction D, the height
a.sub.2 of the structure supporting layer 32 at the first layer and
the height a.sub.2 of the structure supporting layer 32 at the last
layer along the laminating direction D each may be 0.1
.mu.m.about.100 .mu.m, so as to separate the obtained composite
solid electrolyte material and the used substrate, and facilitate
the preparation of the following composite solid electrolyte
membrane 3.
[0067] In the cell according to the first aspect of the present
disclosure, a thickness b.sub.1 of the composite solid electrolyte
membrane 3 (along a direction perpendicular to the direction of the
abutted surface S1) may be 1 .mu.m.about.100 .mu.m, preferably may
be 5 .mu.m.about.30 .mu.m. If the thickness b.sub.1 of the
composite solid electrolyte membrane 3 is too large, the energy
density of the cell prepared from the composite solid electrolyte
membrane 3 will be seriously affected; if the thickness b.sub.1 of
the composite solid electrolyte membrane 3 is too small, the
mechanical processing property of the cell will be affected because
the mechanical strength of the composite solid electrolyte membrane
3 is too weak.
[0068] In the cell according to the first aspect of the present
disclosure, referring to FIGS. 4-5, the cell may further comprise:
at lest a buffer layer 4, the buffer layer 4 is positioned between
the composite solid electrolyte membrane 3 and the positive
electrode plate 1, or the buffer layer 4 is positioned between the
composite solid electrolyte membrane 3 and the negative electrode
plate 2, or the buffer layers 4 are positioned between the
composite solid electrolyte membrane 3 and the positive electrode
plate 1 and between the composite solid electrolyte membrane 3 and
the negative electrode plate 2. Specifically, the two buffer layers
4 may be positioned respectively between the composite solid
electrolyte membrane 3 and the positive electrode plate 1 (in other
words, the composite solid electrolyte membrane 3 is abutted
against the positive electrode plate 1 via one buffer layer 4,
which may be referred as indirect abutting; oppositely, when there
is not the buffer layer 4, the composite solid electrolyte membrane
3 and the positive electrode plate 1 are directly abutted) and
between the composite solid electrolyte membrane 3 and the negative
electrode plate 2 (in other words, the composite solid electrolyte
membrane 3 is abutted against the negative electrode plate 2 via
another buffer layer 4, which may be referred as indirect abutting;
oppositely, when there is not the buffer layer 4, the composite
solid electrolyte membrane 3 and the negative electrode plate 2 are
directly abutted) (referring to FIGS. 4-5) at the same time, or the
buffer layer 4 may be only positioned between the composite solid
electrolyte membrane 3 and the positive electrode plate 1, or the
buffer layer 4 may be only positioned between the composite solid
electrolyte membrane 3 and the negative electrode plate 2.
[0069] In the cell according to the first aspect of the present
disclosure, a material of the buffer layer 4 may be selected from
lithium-containing inorganic salt.
[0070] In the cell according to the first aspect of the present
disclosure, the lithium-containing inorganic salt may be selected
from lithium carbonate, LiF, LiPON or Li.sub.3N.
[0071] In the cell according to the first aspect of the present
disclosure, a thickness b.sub.2 of each layer of the buffer layer 4
may be 1 nm.about.1 .mu.m.
[0072] In the cell according to the first aspect of the present
disclosure, the cell may be selected from a cell of a lithium-ion
battery, a cell of a lithium-ion capacitor, a cell of a sodium-ion
battery or a cell of a sodium-ion capacitor.
[0073] Next, a preparation method of a cell according to a second
aspect of the present disclosure will be described.
[0074] Referring to FIGS. 1-14, a preparation method of a cell
according to a second aspect of the present disclosure, for
preparing the cell according to the first aspect of the present
disclosure, comprises steps of: providing a positive electrode
plate 1; providing a negative electrode plate 2; preparing a
composite solid electrolyte membrane 3: alternately depositing
inorganic solid electrolyte layers 31 and structure supporting
layers 32 on a substrate (not shown) along a laminating direction D
to obtain a composite solid electrolyte material which has an
alternately laminated structure, then separating the composite
solid electrolyte material and the substrate to obtain a composite
solid electrolyte membrane 3, in which the composite solid
electrolyte membrane 3 comprises the inorganic solid electrolyte
layers 31 and the structure supporting layers 32 which are
alternately laminated along the laminating direction D; preparing a
cell: positioning the obtained composite solid electrolyte membrane
3 between the positive electrode plate 1 and the negative electrode
plate 2 to form a cell by winding and/or laminating, in which the
composite solid electrolyte membrane 3 has abutted surfaces S1
respectively abutting against the positive electrode plate 1 and
the negative electrode plate 2, an angle between the laminating
direction D and the abutted surface S1 is defined as .alpha., and
0.degree..ltoreq..alpha.<90.degree..
[0075] In the preparation method of the cell according to the
second aspect of the present disclosure, a material of the
substrate may be one selected from a group consisting of inorganic
non-metallic material, inorganic metallic material and organic
polymer.
[0076] In the preparation method of the cell according to the
second aspect of the present disclosure, the inorganic non-metallic
material may be one selected from a group consisting of glass,
silicon and graphite; the inorganic metallic material may be one
selected from a group consisting of copper, aluminium and iron; the
organic polymer may be one selected from a group consisting of
polytetrafluoroethene and polyamide. These substrates all have
excellent thermal stability and surface flatness, so as to be
easily removed after the deposition process is completed.
[0077] In the preparation method of the cell according to the
second aspect of the present disclosure, the deposition may be
physical vapor deposition.
[0078] In the preparation method of the cell according to the
second aspect of the present disclosure, the physical vapor
deposition may be one selected from a group consisting of vacuum
evaporating, vacuum ion plating, vacuum magnetron sputtering and
vacuum arc plasma plating.
[0079] In the preparation method of the cell according to the
second aspect of the present disclosure, a vacuum degree when the
inorganic solid electrolyte layer 31 is deposited may be 10.sup.-5
Pa.about.10.sup.-2 Pa, a temperature when the inorganic solid
electrolyte layer 31 is deposited may be 200.degree.
C..about.500.degree. C.
[0080] In the preparation method of the cell according to the
second aspect of the present disclosure, when the structure
supporting layer 32 is the polymer layer, a vacuum degree upon
deposition may be 10.sup.-4 Pa.about.10.sup.-1 Pa, a temperature
upon deposition may be 100.degree. C..about.300.degree. C.
[0081] In the preparation method of the cell according to the
second aspect of the present disclosure, when the structure
supporting layer 32 is the polymer electrolyte layer, a vacuum
degree upon deposition may be 10.sup.-4 Pa.about.10.sup.-1 Pa, a
temperature upon deposition may be 100.degree. C..about.300.degree.
C.
[0082] In the preparation method of the cell according to the
second aspect of the present disclosure, referring to FIG. 3 and
FIG. 8, in the step of preparing the composite solid electrolyte
membrane 3, before or after the composite solid electrolyte
material is separated from the substrate (depending on the
practical situation), the composite solid electrolyte material is
cut at an angle of a relative to the laminating direction D to form
the abutted surfaces S1. In FIG. 3, because a cutting direction
(corresponding to the formed abutted surface S1) is parallel to the
laminating direction D, the angle .alpha. is 0.degree. and is not
illustrated, but it is not limited to this. In another method, the
composite solid electrolyte membrane 3 may be directly deposited on
the substrate without the cutting process and the size of the
composite solid electrolyte membrane 3 fully meets the requirement
of the cell. However, the operation difficulty of this method is
relatively big, the production efficiency is relatively low and the
production cost is relatively high. Moreover, as shown in FIGS.
8-11, under the circumstance that the angle .alpha. is not
0.degree., because the composite solid electrolyte membrane 3 is
flushed with the positive electrode plate 1 and the negative
electrode plate 2 at an upper periphery and a lower periphery, when
the positive electrode plate 1 and the negative electrode plate 2
both are rectangular strips, the corners of the structure
supporting layers 32, which are respectively positioned at the top
and the bottom, of the composite solid electrolyte membrane 3 of
FIGS. 8-9 need to be cut away, as shown by an upper dotted line and
a lower dotted line in FIG. 9. In another method, under the
circumstance that the angle .alpha. is not 0.degree., referring to
FIGS. 12-14, adjustment of upper corners and lower corners of the
positive electrode plate 1 and the negative electrode plate 2 is
needed, however, the corners of the structure supporting layers 32,
which are respectively positioned at the top and the bottom, of the
composite solid electrolyte membrane 3 are not needed to be cut
away, therefore the composite solid electrolyte membrane 3 and the
positive electrode plate 1 and the negative electrode plate 2 are
flushed with each other at the upper periphery and the lower
periphery.
[0083] In the preparation method of the cell according to the
second aspect of the present disclosure, a cutting method may be
one selected from a group consisting of mechanical cutting, laser
cutting and plasma cutting.
[0084] In the preparation method of the cell according to the
second aspect of the present disclosure, the preparation method of
the cell according to the second aspect of the present disclosure
may further comprises a step before the step of preparing the cell:
providing a buffer layer 4 (referring to FIGS. 4-5): a buffer layer
4 is deposited on at least one surface selected from a group
consisting of a surface of the positive electrode plate 1 facing
the composite solid electrolyte membrane 3, a surface of the
negative electrode plate 2 facing the composite solid electrolyte
membrane 3, a surface of the composite solid electrolyte membrane 3
facing the positive electrode plate 1 and a surface of the
composite solid electrolyte membrane 3 facing the negative
electrode plate 2, to make the buffer layer 4 positioned between
the composite solid electrolyte membrane 3 and the positive
electrode plate 1, or to make the buffer layer 4 positioned between
the composite solid electrolyte membrane 3 and the negative
electrode plate 2, or to make the buffer layers 4 positioned
between the composite solid electrolyte membrane 3 and the positive
electrode plate 1 and between the composite solid electrolyte
membrane 3 and the negative electrode plate 2. That is the buffer
layer 4 may only be positioned between the composite solid
electrolyte membrane 3 and the positive electrode plate 1, or the
buffer layer 4 may only be positioned between the composite solid
electrolyte membrane 3 and the negative electrode plate 2, or the
two buffer layers 4 may be positioned respectively between the
composite solid electrolyte membrane 3 and the positive electrode
plate 1 and between the composite solid electrolyte membrane 3 and
negative electrode plate 2 (referring to FIGS. 4-5) at the same
time. Referring to FIGS. 4-5, one buffer layer 4 is deposited on
the surface of the positive electrode plate 1 facing the composite
solid electrolyte membrane 3 and another buffer layer 4 is
deposited on the surface of the negative electrode plate 2 facing
the composite solid electrolyte membrane 3, therefore the two
buffer layers 4 are positioned respectively between the composite
solid electrolyte membrane 3 and the positive electrode plate 1 and
between the composite solid electrolyte membrane 3 and the negative
electrode plate 2 at the same time.
[0085] Then examples and comparative examples of the cell and the
preparation method thereof according to the present disclosure
would be described.
Example 1
(1) Providing a Positive Electrode Plate
[0086] Positive active material (lithium cobaltate (LiCoO.sub.2)),
adhesive (polyvinylidene fluoride (PVDF)) and conductive agent
(conductive carbon) according to a mass ratio of 95:3:2 were
uniformly mixed with solvent (N-methyl pyrrolidone (NMP)) to form a
positive electrode slurry, where a solid content of the positive
electrode slurry was 40%, then the positive electrode slurry was
uniformly coated on both surfaces of current collector (aluminum
foil with a thickness of 12 .mu.m) and was then compacted by a
roller machine, which was then followed by cold pressing, cutting,
welding a positive tab, and finally a positive electrode plate was
obtained.
(2) Providing a Negative Electrode Plate
[0087] Negative active material (artificial graphite), thickening
agent (carboxymethyl cellulose sodium), conductive agent
(conductive carbon) and adhesive (styrene-butadiene lattices)
according to a mass ratio of 95:1.5:1.5:2 were uniformly mixed with
solvent (denioned water) to form a negative electrode slurry, where
a solid content of the negative electrode slurry was 50%, then the
negative electrode slurry was uniformly coated on both surfaces of
current collector (copper foil with a thickness of 8 .mu.m) and was
then compacted by a roller machine, which was then followed by cold
pressing, cutting, welding a negative tab, and finally a negative
electrode plate was obtained.
(3) Preparing a Composite Solid Electrolyte Membrane
[0088] At 150.degree. C. and 1.times.10.sup.-3 Pa,
polytetrafluoroethene (PTFE) with a weight-average molecular weight
of 100,000 and a height of 20 .mu.m was deposited on substrate
(copper foil) via vacuum magnetron sputtering to function as the
first layer;
[0089] then inorganic solid electrolyte
(Li.sub.3.25Ge.sub.0.25P.sub.0.75S.sub.4) with a height of 100
.mu.m and PTFE with a height of 1 .mu.m were alternately deposited
on the above copper foil, which was deposited with PTFE, via vacuum
magnetron sputtering respectively under the condition of
200.degree. C. and 1.times.10.sup.-2 Pa and under the condition of
150.degree. C. and 1.times.10.sup.-3 Pa, in which in the alternate
deposition process, the layer number of the inorganic solid
electrolyte layers 31 was bigger than the layer number of the
structure supporting layer 32 by one;
[0090] finally at 150.degree. C. and 1.times.10.sup.-3 Pa, PTFE
with a height of 20 .mu.m was deposited via vacuum magnetron
sputtering to function as the last layer;
[0091] the composite solid electrolyte material having an
alternately laminated structure with a whole height of 50 mm was
obtained, then the composite solid electrolyte material was
separated from the substrate (copper foil), and then 10 .mu.m of
the composite solid electrolyte membrane was cut away along a
direction parallel to the laminating direction D (that was .alpha.
was 0.degree.) via laser cutting, that was the composite solid
electrolyte membrane with a thickness b.sub.1 of 10 .mu.m was
obtained.
(4) Preparing a Cell
[0092] The composite solid electrolyte membrane was positioned
between the positive electrode plate 1 and the negative electrode
plate 2, which were then wound together to form a cell.
Example 2
(1) Providing a Positive Electrode Plate
[0093] It was the same as that in example 1.
(2) Providing a Negative Electrode Plate
[0094] It was the same as that in example 1.
(3) Preparing a Composite Solid Electrolyte Membrane
[0095] At 120.degree. C. and 1.times.10.sup.-2 Pa, polymer
electrolyte with a height of 1 .mu.m comprising polyethylene oxide
(PEO) with a weight-average molecular weight of 600,000 and LiTFSI
(a weight ratio of PEO to LiTFSI was 3:1) was deposited on
substrate (aluminium foil) via vacuum evaporating to function as
the first layer;
[0096] then inorganic solid electrolyte
(Li.sub.2S(75%)-P.sub.2S.sub.5(25%)) with a height of 1 .mu.m and
the above polymer electrolyte with a height of 0.01 .mu.m were
alternately deposited on the above aluminium foil, which was
deposited with the polymer electrolyte, via vacuum evaporating
respectively under the condition of 300.degree. C. and
1.times.10.sup.-3 Pa and under the condition of 120.degree. C. and
1.times.10.sup.-2 Pa, in which in the alternating deposition
process, the layer number of the inorganic solid electrolyte layers
31 was bigger than the layer number of the structure supporting
layers 32 by one;
[0097] finally at 120.degree. C. and 1.times.10.sup.-2 Pa, polymer
electrolyte with a height of 1 .mu.m comprising PEO and LiTFSI (a
weight ratio of PEO to LiTFSI was 3:1) was deposited via vacuum
evaporating to function as the last layer;
[0098] the composite solid electrolyte material with a whole height
of 120 mm was obtained, then before the composite solid electrolyte
material was separated from the substrate (aluminium foil), 18
.mu.m of the composite solid electrolyte membrane was cut away
along a direction parallel to the laminating direction D (that was
.alpha. was 0.degree.) via plasma cutting, that was the composite
solid electrolyte membrane with a thickness b.sub.1 of 18 .mu.m was
obtained.
(4) Preparing a Cell
[0099] The composite solid electrolyte membrane was positioned
between the positive electrode plate 1 and the negative electrode
plate 2, which were then wound together to form a cell.
Example 3
(1) Providing a Positive Electrode Plate
[0100] It was the same as that in example 1.
(2) Providing a Negative Electrode Plate
[0101] It was the same as that in example 1.
(3) Preparing a Composite Solid Electrolyte Membrane
[0102] At 180.degree. C. and 1.times.10.sup.-1 Pa, polymethyl
methacrylate (PMMA) with a weight-average molecular weight of
450,000 and a height of 100 .mu.m was deposited on substrate
(glass) via vacuum evaporating to function as the first layer;
[0103] then inorganic solid electrolyte
(Li.sub.6BaLa.sub.2Ta.sub.2O.sub.12) with a height of 100 .mu.m via
vacuum ion plating at 500.degree. C. and 1.times.10.sup.-3 Pa and
PMMA with a height of 0.1 .mu.m via vacuum evaporating at
180.degree. C. and 1.times.10.sup.-1 Pa were alternately deposited
on the above glass which was deposited with PMMA, in which in the
alternating deposition process, the layer number of the inorganic
solid electrolyte layers 31 was bigger than the layer number of the
structure supporting layers 32 by one;
[0104] finally at 180.degree. C. and 1.times.10.sup.-1 Pa, PMMA
with a height of 100 .mu.m was deposited via vacuum evaporating to
function as the last layer;
[0105] the composite solid electrolyte material with a whole height
of 80 mm was obtained, then the composite solid electrolyte
material was separated from the substrate (glass), and then 30
.mu.m of the composite solid electrolyte membrane was cut away
along a direction parallel to the laminating direction D (that was
.alpha. was 0.degree.) via plasma cutting, that was the composite
solid electrolyte membrane with a thickness b.sub.1 of 30 .mu.m was
obtained.
(4) Preparing a Cell
[0106] The composite solid electrolyte membrane was positioned
between the positive electrode plate 1 and the negative electrode
plate 2, which were then wound together to form a cell.
Example 4
(1) Providing a Positive Electrode Plate
[0107] It was the same as that in example 1.
(2) Providing a Negative Electrode Plate
[0108] It was the same as that in example 1.
(3) Preparing a Composite Solid Electrolyte Membrane
[0109] At 300.degree. C. and 5.times.10.sup.-2 Pa, ultra high
molecular weigh polyethylene (UHMWPE) with a weight-average
molecular weight of Ser. No. 10/000,000 and a height of 100 .mu.m
was deposited on substrate (glass) via vacuum evaporating to
function as the first layer;
[0110] then inorganic solid electrolyte
LiTi.sub.2(PO.sub.4).sub.3--AlPO.sub.4 with a height of 100 .mu.m
and UHMWPE with a height of 10 .mu.m were alternately deposited on
the above glass, which was deposited with UHMWPE, via vacuum
evaporating respectively under the condition of 450.degree. C. and
1.times.10.sup.-5 Pa and under the condition of 300.degree. C. and
5.times.10.sup.-2 Pa, in which in the alternating deposition
process, the layer number of the inorganic solid electrolyte layers
31 was bigger than the layer number of the structure supporting
layers 32 by one;
[0111] finally at 300.degree. C. and 5.times.10.sup.-2 Pa, UHMWPE
with a height of 100 .mu.m was deposited via vacuum evaporating to
function as the last layer;
[0112] the composite solid electrolyte material with a whole height
of 80 mm was obtained, then the composite solid electrolyte
material was separated from the substrate (glass), and then 20
.mu.m of the composite solid electrolyte membrane was cut away
along a direction parallel to the laminating direction D (that was
.alpha. was 0.degree.) via mechanical cutting, that was the
composite solid electrolyte membrane with a thickness b.sub.1 of 20
.mu.m was obtained.
(4) Preparing a Cell
[0113] The composite solid electrolyte membrane was positioned
between the positive electrode plate 1 and the negative electrode
plate 2, which were then wound together to form a cell.
Example 5
(1) Providing a Positive Electrode Plate
[0114] It was the same as that in example 1.
(2) Providing a Negative Electrode Plate
[0115] It was the same as that in example 1.
(3) Preparing a Composite Solid Electrolyte Membrane
[0116] At 150.degree. C. and 2.times.10.sup.-3 Pa, vinylidene
fluoride-hexafluoropropylene copolymer (PVDF-HFP) with a
weight-average molecular weight of 180,000 and a height of 10 .mu.m
was deposited on substrate (glass) via vacuum evaporating to
function as the first layer;
[0117] then inorganic solid electrolyte Li.sub.3N with a height of
20 .mu.m via vacuum arc plasma plating at 350.degree. C. and
5.times.10.sup.-4 Pa and PVDF-HFP with a height of 0.5 .mu.m via
vacuum evaporating at 150.degree. C. and 2.times.10.sup.-3 Pa were
alternately deposited on the above glass which is deposited with
PVDF-HFP, in which in the alternating deposition process, the layer
number of the inorganic solid electrolyte layers 31 was bigger than
the layer number of the structure supporting layers 32 by one;
[0118] finally at 150.degree. C. and 2.times.10.sup.-3 Pa, PVDF-HFP
with a height of 10 .mu.m was deposited via vacuum evaporating to
function as the last layer;
[0119] the composite solid electrolyte material with a whole height
of 200 mm was obtained, then the composite solid electrolyte
material was separated from the substrate (glass), and then 25
.mu.m of the composite solid electrolyte membrane was cut away
along a direction parallel to the laminating direction D (that was
.alpha. was 0.degree.) via mechanical cutting, that was the
composite solid electrolyte membrane with a thickness b.sub.1 of 25
.mu.m was obtained.
(4) Preparing a Cell
[0120] The composite solid electrolyte membrane was positioned
between the positive electrode plate 1 and the negative electrode
plate 2, which were then wound together to form a cell.
Example 6
[0121] The cell was prepared the same as that in example 1 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), after the composite solid electrolyte
material was separated from the substrate (copper foil), 14 .mu.m
of the composite solid electrolyte membrane was cut away along a
direction which was 45.degree. of an angle relative to the
laminating direction D (that was .alpha. was 45.degree.) via laser
cutting, and then the corners of the structure supporting layers
32, which were respectively positioned at the top and the bottom,
of the composite solid electrolyte membrane were cut away, as shown
by the upper dotted line and the lower dotted line in FIG. 9, that
was the composite solid electrolyte membrane with a thickness
b.sub.1 of 10 .mu.m was obtained.
Example 7
[0122] The cell was prepared the same as that in example 1 except
that before the step of preparing a cell (that was step (4)), a
UPON buffer layer with a thickness b.sub.2 of 5 nm was deposited on
the surface of the negative electrode plate facing the composite
solid electrolyte membrane.
Comparative Example 1
[0123] The cell was prepared the same as that in example 1 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), only the inorganic solid electrolyte
was deposited, and a full inorganic solid electrolyte membrane
without polytetrafluoroethene layer was obtained.
Comparative Example 2
[0124] The cell was prepared the same as that in example 2 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), only the inorganic solid electrolyte
was deposited, and a full inorganic solid electrolyte membrane
without the polymer electrolyte layer (the polymer electrolyte
comprised polyethylene oxide and LiTFSI) was obtained.
Comparative Example 3
[0125] The cell was prepared the same as that in example 3 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), only the inorganic solid electrolyte
was deposited, and a full inorganic solid electrolyte membrane
without polymethyl methacrylate layer was obtained.
Comparative Example 4
[0126] The cell was prepared the same as that in example 4 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), only the inorganic solid electrolyte
was deposited, and a full inorganic solid electrolyte membrane
without ultra high molecular weigh polyethylene layer was
obtained.
Comparative Example 5
[0127] The cell was prepared the same as that in example 5 except
that in the step of preparing a composite solid electrolyte
membrane (that was step (3)), only the inorganic solid electrolyte
was deposited, and a full inorganic solid electrolyte membrane
without vinylidene fluoride-hexafluoropropylene copolymer layer was
obtained.
[0128] Finally testing processes and test results of examples 1-7
and comparative examples 1-5 would be described.
(1) Testing of the Young Modulus of Solid Electrolyte Membranes
[0129] The Young modulus of the composite solid electrolyte
membranes of examples 1-7 and the Young modulus of the full
inorganic solid electrolyte membranes of comparative examples 1-5
were tested with a Young modulus tester with the method of
photo-leverage.
(2) Testing of the Lithium Ionic Conductivity of Symmetric
Cells
[0130] Two lithium plates each with a thickness of 100 .mu.m and
two copper foils each with a thickness of 8 .mu.m were compounded
respectively to function as a positive electrode plate and a
negative electrode plate respectively (that was one lithium plate
and one copper foil were compounded into the positive electrode
plate, the other lithium plate and the other copper foil were
compounded into the negative electrode plate), the composite solid
electrolyte membranes of examples 1-7 and the full inorganic solid
electrolyte membranes of comparative examples 1-5 were functioned
as the solid electrolyte membrane, then the positive electrode
plate, the negative electrode and the solid electrolyte membrane
were laminated to form a symmetric cell, EIS testing was conducted
under 5 mV and 0.03 Hz-500000 Hz, finally the lithium ionic
conductivity of the symmetric cell was calculated.
[0131] Table 1 illustrated the test results of examples 1-7 and
comparative examples 1-5.
TABLE-US-00001 TABLE 1 Test results of examples 1-7 and comparative
examples 1-5 Young modulus lithium ionic conductivity (Gpa) (mS/cm)
Example 1 1.1 11.7 Example 2 1.7 2.5 Example 3 12.1 4 .times.
10.sup.-2 Example 4 8.3 3 .times. 10.sup.-1 Example 5 25.6 8
.times. 10.sup.-3 Example 6 1.6 10.5 Example 7 1.1 11.3 Comparative
example 1 18 10.3 Comparative example 2 25 2.3 Comparative example
3 234 4 .times. 10.sup.-2 Comparative example 4 117 3 .times.
10.sup.-1 Comparative example 5 1023 7 .times. 10.sup.-3
[0132] It could be seen from a comparison between examples 1-7 and
comparative examples 1-5, compared with the full inorganic solid
electrolyte membrane, the Young modulus of the composite solid
electrolyte membrane of the present disclosure was greatly
decreased. It was concluded that, the composite solid electrolyte
membrane of the present disclosure effectively improved the
elasticity and the mechanical processing property of the inorganic
solid electrolyte membrane.
[0133] It could also be seen from a comparison between examples 1-7
and comparative examples 1-5, compared with the symmetric cell
prepared from the full inorganic solid electrolyte membrane, the
lithium ionic conductivity of the symmetric cell prepared from the
composite solid electrolyte membrane of the present disclosure
didn't show any significant reduction. It was concluded that, the
composite solid electrolyte membrane of the present disclosure
could ensure the stability of the structure of the inorganic solid
electrolyte in the preparation process, thereby ensuring a high
lithium ionic conductivity of the symmetric cell using the
composite solid electrolyte membrane.
* * * * *